Modelling of the climatic river runoff for the Siberian region - PowerPoint PPT Presentation

Modelling of the climatic river runoff for the Siberian region V.I.Kuzin, N.A. Lapteva Institute of Computational Mathematics & Mathematical Geophysics, RAS, Novosibirsk, Russian Federation Email: kuzin@sscc.ru ENVIROMIS-2012

Content • Role of the Arctic ocean in the global hydrological cycle • Influence that interannual variability of the Siberian rivers has to the fresh water balance in the Arctic ocean • Hydrological discharge model • Simulation of the river runoff with the use of the NCEP/ NCAR and ERA40 reanalysis data • Conclusion

Global hydrological cycle (th. km 3 /y)

Scheme of the World ocean circulation

Arctic basin and the main rivers Arctic ocean form 5% of total area of the World ocean (14.4 mln km 2 , Ivanov, 1976) and 1% of its volume. However it gives input 11% of total rivers water into the World Ocean (Kalinin, Shiklomanov, 1972). Siberian rivers gives about 55% of the total volume, McKenzie - 5 %, the Bering strait gives about 40% with variability 25-30%. Increasing trend 2.9+0.4 km 3 /y (Agaard, Karmak, 1989, Sereze et al, 2006, Woodgate et al, 2006, Shiklomanov, 2010).

Conceptual model of the Arctic hydrological cycle, with key linkages among land, ocean, and atmosphere (Water System Analysis Group, Univ. of New Hampshire) A = atmospheric boundary fluxes B = atmospheric dynamics C = land-surface atmosphere exchanges (with vegetation and permafrost dynamics) D= discharge through well-defined flow networks (with groundwater and river channel flow) E = runoff from poorly organized lowland flow systems F = sea ice mass balance and dynamics G = estuarine controls on terrestrial/shelf interactions H= changes in glacial mass balance and associated runoff I = direct groundwater discharge to ocean J = Arctic Ocean dynamics and deep water formation K = biological dynamics and oceanic food chains

MOTIVATION FOR THE CONSTRUCTION THE RIVER RUNOFF MODEL A numerical simulation with a 3D ICM&MG hydro-thermodynamical model of the Arctic and North Atlantic oceans is used to study the influence that the interannual variations in the Siberian river discharge have on the distribution and propagation of freshwater in this region. In numerical experiments we compared simulations with the use of observational data on the discharge of the most significant Siberian rivers (Ob, Yenisei, and Lena) against the results of climatic seasonally average variations of their discharges. 55 53 50 48 45 43 40 1930 1940 1950 1960 1970 1980 1990 Total volume transport of Yenisei +Lena +Ob Rivers ( th. cubic m/s)

Coupled Ice-Ocean Model 3D Ocean Circulation Model of ICMMG based on z-level vertical coordinate approach (Kuzin1982, Golubeva at al.,1992, Golubeva,[2001], Golubeva and Platov,[2007]) Ice model-CICE 3.14 (elastic-viscous-plastic) W.D.Hibler ,1979, E.C.Hunke, J.K.Dukowicz,1997, G.A.Maykut 1971 C.M.Bitz, W.H.Lipscomb 1999,J.K.Dukowicz, J.R.Baumgardner 2000, W.H.Lipscomb, E.C.Hunke 2004

Interannual variability of the Siberian rivers discharge. Difference in the volumes between the observed and climatic discharges of Siberian rivers accumulated since 1948. Movement of the positive anomaly of the fresh water since 1958.

Scheme of regional subsurface circulation and changes made by fresh river waters. (a): Wide arrow line across the basin is Transpolar drift current (TDC), on its left - Atlantic water current, on its right - Beaufort Gyre. Line AB shows the section position presented on (b): vertical section across TDC. When FW volume grows, pressure gradient in subsurface layer increases also and makes the gradient component of velocity stronger (thin dashed arrows on (a)), thus the Atlantic water current and TDC weaken in subsurface layer.

Coefficients of correlation of accumulated river discharge with the total loss through the main straits, as well as losses of freshwater though these straits. (1) - correlation coefficient at the maximum level with respect to the significance level, (2) – time lag prior to the maximum response (in years) to the river discharge anomaly. Straits 1 2 Total loss through the straits -0,78 4 Fram Strait Canadian Archipelago 0,59 0 (0,71) (12) Barents Sea 0,74 4 Freshwater discharge Fram Strait -0,75 6 Canadian Archipelago 0,57 0 (0,71) (12) Barents Sea 0,40 7

Relief of the regional climatic hydrological discharge model and the main Siberian rivers of the model (1/3 deg. res.)

Main features of the linear Hydrological Discharge Model (Kutchment, 1972,1989, Burakov, 1978, etc.) Structure of MPI, Hamburg, 1998, Model is constructed from linear reservoirs in the grid boxes: • Velocity of the out flow depends linearly from the inflow and proportional to the slope of the grid box and untiproportional to the gridbox length. • Velocity of the outflow from the reservoirs or cascade of the reservoirs are found on the basis of the solution of the ordinary differential equations The lateral water flow separates into three flow processes: • Overland flow • Base flow • River flow • In the each gridbox the parameterization of the wetlands and lakes is included

Velocity of the outflow from the reservoir or the cascade of the reservoirs are determined from the solution of the solution of the differential equations (for ex. Kalinin, Miliukov, 1958) dQ ( t ) k I ( t ) Q ( t ) ⋅ = − (1) dt where k –time retention coefficient for the reservoir, I(t) – inflow, Q(t) –outflow from the reservoir. For the cascade of n reservoirs the consequence of n equations is solved dQ ( t ) k i I ( t ) Q ( t ) i 1 ,..., n ⋅ = − = (2) i i dt Q I , I I ( t ) , Q Q ( t ) = = = i i 1 1 n +

General solution of the equation (1) with the zero initial conditions is the convolution of I(t) with the function h(t) ∞ (3) Q ( t ) I ( ) h ( t ) d = ∫ τ ⋅ − τ ⋅ τ 0 Here h(t) is system function, which is the simplest variant has the form t = 1 − (4) h ( t ) e k ⋅ k For the cascade of n reservoirs system function has a form (5) t n 1 t − − h ( t ) e k = ⋅ n k ( n 1 )! ⋅ −

Structure of the HD MODEL Each gridbox has 8 directions of the outflow to the neighboring grid boxes : N, E, S, W, N Е , SE, SW, NW, which is defined by the slope of the gridbox by unique manner.

Siberian rivers watersheds. Discharge parsways.

Wetland and lakes parameterization in the HD model Wetlands is parameterized by retention coefficient f W , which influenced to the velocity of the overland flow and river flow and depends on the wetland fraction p W : 1 ⎛ − ⎞ ν (10) W , i ( ( ( ) ) ) f 1 1 tanh 4 p p 1 ⎜ ⎟ = − ⋅ π ⋅ − + W , i W c ⎜ ⎟ 2 ν ⎝ ⎠ 0 , i The retention time is determined as: x Δ k n 1 (11) = = i i f ⋅ ν W , i 0 , i x Δ ν = (12) 0 , i n k ⋅ i i Lakes parameterization is introduced by the analogous formulas with the use of the pretension coefficient f L .

Precipitation - Evaporation + Snowmelt (PES). Ob River watershed (km 3 ). NCEP, ERA40 reanalysis data. 700 700 NCEP ERA 600 600 500 500 400 400 300 300 200 200 100 100 0 0 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1958-1968 1969-1979 1980-1990 1991-2001 1958-2001 1958-1968 1969-1979 1980-1990 1991-2001 1958-2001 600 PES values for the 12 months 500 averaged during 11 years periods from 1958-2001 400 (upper diagrams) 300 200 Climatic values of PES for the NCEP (blue) and ERA40 (red) 100 reanalysis (bottom). 0 1 2 3 4 5 6 7 8 9 10 11 12 1958-2001 (ERA) 1958-2001 (NCEP)

Ob River runoff NCEP 120 90 Runoff values for the 12 60 months averaged during period from 1958 - 2001 30 NCEP reanalysis (blue) (upper diagram) 0 1 2 3 4 5 6 7 8 9 10 11 12 1958-1968 1969-1979 1980-1990 1991-2001 Climatic values of runoff for the 1958-2001 Measurements ERA40 reanalysis (red) (bottom). ERA 120 Climatic runoff from the 90 measurements on the Ob – Salechard hydrometeostation 60 1936 – 1990 (black). 30 0 1 2 3 4 5 6 7 8 9 10 11 12 1958-1968 1969-1979 1980-1990 1991-2001 1958-2001 Measurements

Ob River runoff (km 3 ) 100 Annual runoff averaged for the period 1958-2001 80 60 500 456 400 396 400 40 300 20 200 100 0 1 2 3 4 5 6 7 8 9 10 11 12 0 ERA NCEP Measurements 1958-2001 (ERA) 1958-2001 (NCEP) Measurements 700 600 500 Annual runoff for the period 1958-2001 400 300 200 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 ERA NCEP Measurements

Precipitation - Evaporation + Snowmelt (PES). Yenisei River watershed (km 3 ). 1000 1000 ERA NCEP 800 800 600 600 400 400 200 200 0 0 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1958-1968 1969-1979 1980-1990 1991-2001 1958-2001 1958-1968 1969-1979 1980-1990 1991-2001 1958-2001 800 PES values for the 12 months 700 averaged during 11 years 600 periods from 1958-2001 500 (upper diagrams) 400 300 Climatic values of PES for the 200 NCEP (blue) and ERA40 (red) 100 reanalysis (bottom). 0 1 2 3 4 5 6 7 8 9 10 11 12 1958-2001(ERA) 1958-2001(NCEP)